1. Field of the Invention
The present invention relates to network planning, and in particular, to determining a network topology for placing rings in a telecommunications network.
2. Description of the Prior Art
Network planning involves determining where, when and how much new capacity, i.e., carrier facilities, must be added to the network in order to meet a demand for services through the network. The demand is described in a point to point demand forecast of traffic requirements between every pair of points in the network.
Many existing asynchronous telecommunications networks were planned using expert system techniques. The use of expert system techniques was feasible because the asynchronous networks were well understood by network engineers, and it was thus possible to develop a set of rules that could be applied by the expert system.
The telecommunications industry is, however, changing with an introduction of a synchronous technology know as a Synchronous Optical Network (SONET). SONET will likely replace nearly all telecommunications facilities. SONET, like its asynchronous counterpart, is a facility that carries telecommunications traffic in a network. Unlike asynchronous facilities that only connect two points in a direct link, SONET allows several points to be connected. Furthermore, these several points may be connected in two different types of architectures, i.e., a ring and a chain. The ring architecture is desirable because it is xe2x80x9cself-healingxe2x80x9d in a case of a cable cut.
The ring and chain architectures are a radical departure from the traditional point to point connections of the asynchronous facilities. The introduction of the ring and chain architectures significantly increases the number of alternative routing configurations available to network planners for meeting forecasted demands. Rather than merely connecting points in the network in a pair-wise manner with direct connections, network engineers must now determine sets of points that are to be connected, and the topology that should be used.
Ring placement is a particularly challenging task as a ring could be either unidirectional or bi-directional, each of which is suited for a particular type of traffic pattern. Furthermore, in the case of a SONET ring, the points on the ring must be connected in a circular, non-overlapping fiber optic path.
Ring architectures are also being incorporated into a telecommunications technology called Dense Wave Division Multiplexing (DWDM)/Optical rings. In Dense Wave Division Multiplexing, multiple colors of light are passed through a single fiber optic strand, thus permitting multiple signals through that strand. This increases the capacity of each fiber optic strand. In addition, Optical add/drop multiplexers (ADMs) are being developed in conjunction with DWDM technology to provide self-healing ring architectures based on light wave signals.
It is an object of the present invention to provide an improved method for determining a network topology.
It is another object of the present invention to provide such a method in which the topology is determined by performing a state space search of potential solutions defining various network topologies.
It is a further object of the present invention to provide such a method that places rings into the network.
It is yet a further object of the present invention to provide such a method that places rings in a SONET ring network or a Dense Wave Division Multiplexing (DWDM)/Optical ring network.
These and other objects of the present invention are achieved by a method for determining a topology of a network comprising the steps of obtaining data that describes a requirement for a service between a first node and a second node, and searching a state space to define a solution that fulfills the requirement, wherein the solution provides a topographic arrangement for the first node and the second node in the network. There is also provided a system for determining a topology of a network.